The present invention relates to a front body structure of a vehicle, and in particular, relates to a front body structure of a vehicle equipped with a laterally-extending member which is provided in front of and below a bumper reinforcement and supported at a front side frame.
Conventionally, in order to prevent a secondary injury of a pedestrian, such as for preventing a pedestrian from being caught under the vehicle, at a collision of the vehicle with the pedestrian, a control of sweeping away the pedestrian's leg part so that the pedestrian can be surely put on an engine hood of the vehicle has been developed. Thus, a front body structure of a vehicle equipped with a laterally-extending member which is provided below a bumper reinforcement and supported at a shroud lower member so as to extend in a vehicle width direction, i.e., a so-called leg-part sweeping-away member, is known.
The leg-part sweeping-away member requires its crushable longitudinal length which is long enough to absorb the collision energy through its crushing in the vehicle longitudinal direction when the vehicle hits against the pedestrian. However, in case a radiator slants so that an upper side thereof is positioned forwardly in the vehicle longitudinal direction for a low engine-hood layout of the vehicle, the shroud lower member is disposed at a rear portion of the vehicle, so that the leg-part sweeping-away member would be long and thereby the vehicle weight would become heavy.
Japanese Patent Laid-Open Publication No. 2001-88634 discloses a vehicle body structure which comprises a pair of support members which is fixed to a pair of front side frames, and a leg-part sweeping-away member as a laterally-extending member which is supported at this support member and extends in the vehicle width direction is provided in front of and below a bumper reinforcement, wherein the leg-part sweeping-away member is deformable by the collision energy with the pedestrian. According to this vehicle body structure, the leg-part sweeping-away member can be supported at the front side frames firmly and the impact load of the collision can be absorbed by the leg-part sweeping-away member, so that the safety of the leg part of the pedestrian can be properly secured.
Meanwhile, in order to decrease the impact load against a passenger at the vehicle frontal collision, a deformation mode control to absorb collision energy with the front side frames which are deformed by the collision energy inputted to the front side frames has been materialized. For example, a crush can arranged at a front end of the front side frame is crushed in an initial stage of collision, and the front side frame is bent outwardly in the vehicle width direction, in a plan view, having a bending center at its connection portion to a dash panel in a middle stage of collision or later. Thus, the vehicle deceleration is controlled so that it can become properly large in the initial stage of collision, and then its vehicle deceleration can be maintained.
In the above-described vehicle body structure, the leg-part sweeping-away member is firmly fixed to the front side frame with the support member, such as a high-rigidity bracket or a tie-down hook. However, the support member increases the plate thickness of the front side frame and thereby strengthens the rigidity of the frame, so that there is a concern that the crush deformation of the front side frame may be so hindered that any desired effect of the collision-energy absorption due to the deformation mode control may not be obtained. Additionally, the support member with the high rigidity may cause the heavy vehicle weight.
Further, since the above-described leg-part sweeping-away member is formed to be deformable by the collision energy, it may be required that the longitudinal length of the leg-part sweeping-away member may be long enough to have this member deformed by the collision load, so that there is a concern that the leg-part sweeping-away member itself may become improperly large sized. In case the leg-part sweeping-away member itself becomes improperly large sized, there is a concern that the layout of an attachment position of the support member to the front side frame or the like may be so limited because the leg-part sweeping-away member is necessary to be fixed to the front side frame, and additionally the vehicle weight may increase.